1. Field of the Invention
The present invention relates to work stations or work holders employed in automatic wire bonders and more particularly to a modular work station or work holder which is adapted to be rapidly removed and rapidly replaced by another modular work station to minimize down time in an automatic wire bonder.
2. Description of the Prior Art
The present invention is an improvement of prior art work holders or work stations which have been incorporated into automatic wire bonders made by Kulick and Sofa Industries, Inc. of Willow Grove, Pa. under model designations 1481 and 1482. Such automatic wire bonders are commercially available and have heretofore had dedicated work holders or work stations adapted to receive lead frames. Such work stations may be changed by disassemblying and reassemblying or partially rebuilding the automatic wire bonder. Such changes require an inordinate amount of time. Such prior art work stations are coupled to or connected to at least three mechanical drives, one for advancing the lead frame, one for positioning the lead frame on the bonding station and one or more drives for clamping the lead frame in the station. When another work station of different size was required to accommodate a different size lead frame in the prior art, individual parts of the prior art work station were moved, disassembled, and/or removed in the process of rebuilding a new work station into an automatic wire bonder.
Work stations or work holders for prior art manual or semiautomatic wire bonders did not employ automatic indexing, automatic positioning, automatic clamping of the lead frame and other automatic sensing operations, thus, could be considered integral units which could be replaced rapidly because there were none of the aforementioned mechanical drives connected to the work station.
Heretofore, it was necessary to employ a highly skilled technician trained to set up and test a production machine under process conditions whenever an automatic wire bonder required a new work station change because the drive mechanisms, feed mechanisms, positioning mechanisms as well as clamping and sensing mechanisms were changed with a work station change on the prior art type automatic wire bonders.
Quite often a plurality of automatic wire bonders are monitored by a single operator. When one of the automatic wire bonders is out of service, the production of the machine is lost and the prorata share of the time of the operator is lost thus increasing the cost of operation of the remaining machines. In modern production facilities expensive automatic wire bonders cannot be dedicated to low production items or even to batch production which is intermittent. The most economical production use of such automatic wire bonders has heretofore been to keep the bonder on line as long as possible during a work shift.
It would be extremely desirable to provide a modular work station or work holder for an automatic wire bonder which would permit changing from one lead frame in production to another size lead frame in production in minutes instead of hours and would then require only the minimum change of electronic data input to the automatic wire bonders computer to commence production employing the new lead frame.